How To Diagnose DBW Issues
If you are having DBW issues, this will be a step by step on what to look for to try and solve them.
As always, if you are stuck, give tech support a call at 888-298-8116, or shoot us a email at USA@Haltech.com.
First, open the DBW Diag page that is pre loaded in the NSP software. It will look like this below:
From here, you can see all you need to diagnose most DBW issues you might have. There are other channels, like "DBW Disable Reason" that are also helpful, but learning to read the voltages is also a good skill to have.
The top trace view has APP A&B voltage, as well as the supervisors voltages for those inputs. The supervisor is what the ECU learns in the calibration process, and it is what the actual voltages should match at all times. If they are not matching exactly this would mean you have an issue with the APP sensor, or the wiring that has happened since the calibration process was done. If neither of those APP A&B voltages move with the pedal moving, that could also mean you have a pedal or wiring issue.
The middle trace view has the DBW TPS A&B, as well as the supervisors for those inputs. The supervisor is what the ECU learns in the calibration process, and is what the actual voltages should match at all times. If they are not matching, then this would mean that the DBW throttle is not sending out the same voltage per position as it did in the calibration and you would need to check the wiring or the DBW throttle itself to see why this has changed.
The lower trace view is the DBW target verse the actual. This is where the ECU is commanding the DBW to go, and where it actually is. These should always match unless there is a issue with the DBW throttles ability to go to that position, or you do not have the ECU power supply ran with enough power to drive the throttle correctly.
The trace view to the right of that is the DBW duty cycle. If the DC % is making out at -100% or 100%, that means the ECU is commanding the DBW throttle to move with as much force as it has available. This is not something that should happen often, and can mean a failing DBW throttle or poor wiring connection the DBW throttle to the ECU. It can also happen if you are trying to drive a throttle that needs more amps than the ECU can provide, which is rare, but can happen in some ITB situation when the ITB's are not sync'd properly and bind up.
The rest of the data on the right of the page is related to the error the ECU is seeing from actual to supervisor for each input and then again for each component (pedal and throttle). You can see this on the trace views as well, so it is semi redundant.
The image above is also from a working car, so you can see what the views should look like, but the voltages and shapes of the patterns will be dependent on your parts used.
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